Nanoscale analysis of symmetry and molecular membrane topography

ended

The compositional and structural asymmetry of cell membranes remains one of the greatest knowledge gaps in cell biology. Cells invest significant amount of energy to establish and maintain inter-leaflet asymmetry; however, the physiological roles of bilayer lipids during dynamic cellular processes in eukaryote membranes remain poorly understood, mostly due to the limits of previously available methodologies and the complexity of lipid membranes. Current knowledge originates from indirect and perturbing techniques (i.e. enzymatic digestion and mass spectrometry) which significantly limits the applicability to certain cell types with no internal membranes. Moreover, these bulk methods do not provide spatial information on lipid asymmetry which prevents detailed observation of subcellular changes during dynamics processes such as host-pathogen interactions. In this project, I will develop a method to directly visualize and quantify membrane asymmetry, which will be applicable to study any cell type as well as intracellular membranes. Recent advances in super-resolution microscopy, including my latest publications, paved the way for direct observation and quantification of lipid asymmetry. I will combine state-of-the-art isotropic expansion methods with super-resolution microscopy to visualize membrane lipids in individual leaflets of bilayers. To obtain further insights on the physiological role of membrane asymmetry, I will investigate changes in lipid asymmetry induced by infection with viral particles. The novel methods I will develop will significantly contribute to a better understanding of lipid asymmetry in biological membranes and its impact in cellular physiology and diseases mechanisms.